By Ken Kurko, Process Safety Services Director, Fauske & Associates, LLC
Colder temperatures mean lower sample reactivity at those temperatures (less heat generation) so, shipping is generally safer from a UN testing perspective. But, there is one thing that comes to mind relating to problems that could arise from dropping temperatures. If a container of a liquid chemical becomes frozen due to colder conditions (whether it be during shipping or storage), the container will have to be heated up to melt the chemical before use. If it is simply moved to a warmer room, it could take several days to thaw depending on the quantity of material and temperatures involved. Sometimes, people will throw band heaters on these frozen containers to expedite the thawing process. Incidents have been caused by people accidentally heating the containers too much (sometimes way past the melting point), causing runaway reactions. The following link discusses this issue in depth for a common industrial solvent, DMSO:
Here is another useful link, an acrylic acid handling guide by Arkema, BASF, and Dow Chemical. In section 6.2, it describes the issue in depth for a monomer. Later on, it also talks about avoiding using acrylic acid from a partially thawed container. This thawed material could be void of inhibitor, making it much more hazardous.
Later on, it also talks about avoiding using acrylic acid from a partially thawed container. This thawed material could be void of inhibitor, making it much more hazardous.
The ways to prevent such an occurrence extend back to truly understanding the characteristics and reactivity of the chemical you are using – what temperature or pressure can incite a negative reaction, and have safe handling processes in place. MSDS information and testing can help.
Ideally, the most obvious manner of prevention is to avoid the chemical freezing if at all possible. However, if you think there is a chance you will need to thaw before use, incorporate the safe thawing time into the process schedule to ensure that it thaws safely. This is definitely one of those situations where proceeding ‘low and slow’ can make a huge difference between the desirable outcome and disaster.
If you are unsure of proper chemical process safety including handling in colder temperatures, our engineers can help. Please feel free to contact me at Ken Kurko, 630-887- 5266, Kurko@fauske.com for more information. www.fauske.com